Support apparatus, lithographic apparatus and device manufacturing method

ABSTRACT

A support apparatus for a lithographic apparatus has an object holder and an extraction body radially outward of the object holder. The object holder is configured to support an object. The extraction body includes an extraction opening configured to extract fluid from a top surface of the support apparatus. The extraction body is spaced from the object holder such that the extraction body is substantially decoupled from the object holder. The extraction body comprises a projection configured such that it surrounds the object holder and such that, in use, a layer of liquid is retained on the projection and in contact with an object supported on the object holder.

This application is a continuation of U.S. patent application Ser. No.15/297,001 which was filed on Oct. 18, 2016, now allowed, which is acontinuation of U.S. patent application Ser. No. 14/403,114, filed Nov.21, 2014, now U.S. Pat. No. 9,507,275, which is the U.S. national phaseentry of POT patent application no. PCT/EP2013/060218, which was filedon May 17, 2013, which claims the benefit of priority of U.S.provisional application No. 61/652,582, which was filed on May 29, 2012,and U.S. provisional application No. 61/666,348, which was filed on Jun.29, 2012, each of which applications is incorporated herein in itsentirety by reference.

FIELD

The present invention relates to a support apparatus, a lithographicapparatus and a device manufacturing method.

BACKGROUND

A lithographic apparatus is a machine that applies a desired patternonto a substrate, usually onto a target portion of the substrate. Alithographic apparatus can be used, for example, in the manufacture ofintegrated circuits (ICs). In that instance, a patterning device, whichis alternatively referred to as a mask or a reticle, may be used togenerate a circuit pattern to be formed on an individual layer of theIC. This pattern can be transferred onto a target portion (e.g.comprising part of, one, or several dies) on a substrate (e.g. a siliconwafer). Transfer of the pattern is typically via imaging onto a layer ofradiation-sensitive material (resist) provided on the substrate. Ingeneral, a single substrate will contain a network of adjacent targetportions that are successively patterned. Known lithographic apparatusinclude so-called steppers, in which each target portion is irradiatedby exposing an entire pattern onto the target portion at one time, andso-called scanners, in which each target portion is irradiated byscanning the pattern through a radiation beam in a given direction (the“scanning”-direction) while synchronously scanning the substrateparallel or anti-parallel to this direction. It is also possible totransfer the pattern from the patterning device to the substrate byimprinting the pattern onto the substrate.

It has been proposed to immerse the substrate in the lithographicprojection apparatus in a liquid having a relatively high refractiveindex, e.g. water, so as to fill a space between the final element ofthe projection system and the substrate. In an embodiment, the liquid isdistilled water, although another liquid can be used. An embodiment ofthe invention will be described with reference to liquid. However,another fluid may be suitable, particularly a wetting fluid, anincompressible fluid and/or a fluid with higher refractive index thanair, desirably a higher refractive index than water. Fluids excludinggases are particularly desirable. The point of this is to enable imagingof smaller features since the exposure radiation will have a shorterwavelength in the liquid. (The effect of the liquid may also be regardedas increasing the effective numerical aperture (NA) of the system andalso increasing the depth of focus.) Other immersion liquids have beenproposed, including water with solid particles (e.g. quartz) suspendedtherein, or a liquid with a nano-particle suspension (e.g. particleswith a maximum dimension of up to 10 nm). The suspended particles may ormay not have a similar or the same refractive index as the liquid inwhich they are suspended. Other liquids which may be suitable include ahydrocarbon, such as an aromatic, a fluorohydrocarbon, and/or an aqueoussolution.

Submersing the substrate or substrate and substrate table in a bath ofliquid (see, for example, U.S. Pat. No. 4,509,852) means that there is alarge body of liquid that must be accelerated during a scanningexposure. This requires additional or more powerful motors andturbulence in the liquid may lead to undesirable and unpredictableeffects.

In an immersion apparatus, immersion fluid is handled by a fluidhandling system, device structure or apparatus. In an embodiment thefluid handling system may supply immersion fluid and therefore be afluid supply system. In an embodiment the fluid handling system may atleast partly confine immersion fluid and thereby be a fluid confinementsystem. In an embodiment the fluid handling system may provide a barrierto immersion fluid and thereby be a barrier member, such as a fluidconfinement structure. In an embodiment the fluid handling system maycreate or use a flow of gas, for example to help in controlling the flowand/or the position of the immersion fluid. The flow of gas may form aseal to confine the immersion fluid so the fluid handling structure maybe referred to as a seal member; such a seal member may be a fluidconfinement structure. In an embodiment, immersion liquid is used as theimmersion fluid. In that case the fluid handling system may be a liquidhandling system. In reference to the aforementioned description,reference in this paragraph to a feature defined with respect to fluidmay be understood to include a feature defined with respect to liquid.

Handling immersion liquid in a lithographic apparatus brings with it oneor more problems of liquid handling. A gap normally exists between anobject, such as a substrate and/or a sensor, and a table (e.g. asubstrate table or a measurement table) around the edge of the object(e.g., substrate and/or sensor). U.S. patent application publication US2005-0264778 discloses filling that gap with material or providing aliquid source or low pressure source to deliberately fill the gap withliquid in order to avoid bubble inclusion as the gap passes under theliquid supply system and/or to remove any liquid which does enter thegap.

SUMMARY

It is desirable, for example, to improve the stability of thetemperature profile of an object holder of a lithographic apparatus.

According to an aspect, there is provided a support apparatus for alithographic apparatus, comprising: an object holder configured tosupport an object; and an extraction body radially outward of the objectholder, the extraction body comprising an extraction opening configuredto extract fluid from a top surface of the support apparatus, whereinthe extraction body is spaced from the object holder such that theextraction body is substantially decoupled from the object holder;wherein the extraction body comprises a projection configured such thatit surrounds the object holder and such that, in use, a layer of liquidis retained on the projection and in contact with an object supported onthe object holder.

According to an aspect, there is provided a support apparatus for alithographic apparatus, comprising: an object holder; and an extractionbody radially outward of the object holder, the extraction bodycomprising an extraction opening configured to extract fluid from a topsurface of the support apparatus, wherein the extraction body isconnected to the object holder by a plurality of peripherally spacedjoints such that, between the joints, the extraction body is spaced fromthe object holder.

According to an aspect, there is provided a device manufacturing methodusing a lithographic apparatus, the method comprising: projecting a beampatterned by a patterning device onto a substrate while supporting thesubstrate with a support apparatus, wherein the support apparatuscomprises: an object holder configured to support an object; and anextraction body radially outward of the object holder, the extractionbody comprising an extraction opening configured to extract fluid from atop surface of the support apparatus, wherein the extraction body isspaced from the object holder such that the extraction body issubstantially decoupled from the object holder; wherein the extractionbody comprises a projection configured such that it surrounds the objectholder and such that, in use, a layer of liquid is retained on theprojection and in contact with an object supported on the object holder.

According to an aspect, there is provided a device manufacturing methodusing a lithographic apparatus, the method comprising: projecting a beampatterned by a patterning device onto a substrate while supporting thesubstrate with a support apparatus, wherein the support apparatuscomprises: an object holder; and an extraction body radially outward ofthe object holder, the extraction body comprising an extraction openingconfigured to extract fluid from a top surface of the support apparatus,wherein the extraction body is connected to the object holder by aplurality of peripherally spaced joints such that, between the joints,the extraction body is spaced from the object holder.

According to an aspect, there is provided a support apparatuscomprising: a table formed of a table material having a thermalconductivity; a body positioned within a recess of the table, whereinthere is a gap between the body and the table; and a member bridging thegap from a top surface of the body to a top surface of the table, themember comprising a thermal resistance layer of thermal resistancematerial having a lower thermal conductivity than the thermalconductivity of the table material.

According to an aspect, there is provided a device manufacturing methodusing a lithographic apparatus, the method comprising: projecting a beampatterned by a patterning device onto a substrate while supporting thesubstrate with a support apparatus, wherein the support apparatuscomprises: a table formed of a table material having a thermalconductivity; a body positioned within a recess of the table, whereinthere is a gap between the body and the table; and a member bridging thegap from a top surface of the body to a top surface of the table, themember comprising a thermal resistance layer of thermal resistancematerial having a lower thermal conductivity than the thermalconductivity of the table material.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of exampleonly, with reference to the accompanying schematic drawings in whichcorresponding reference symbols indicate corresponding parts, and inwhich:

FIG. 1 depicts a lithographic apparatus according to an embodiment ofthe invention;

FIGS. 2 and 3 depict a liquid supply system for use in a lithographicprojection apparatus;

FIG. 4 depicts a further liquid supply system for use in a lithographicprojection apparatus;

FIG. 5 depicts a further liquid supply system for use in a lithographicprojection apparatus;

FIGS. 6-8 depict, in cross-section, a part of a support apparatus of anembodiment;

FIG. 9 depicts, in plan, a part of a support apparatus of an embodiment;

FIGS. 10-14 depict, in cross-section, a part of a support apparatus ofan embodiment;

FIGS. 15-19 depict, in cross-section, a thermal conditioning system ofan embodiment;

FIGS. 20-30 depict, in cross-section, a part of a support apparatus ofan embodiment.

DETAILED DESCRIPTION

FIG. 1 schematically depicts a lithographic apparatus according to oneembodiment of the invention. The apparatus comprises:

-   -   an illumination system (illuminator) IL configured to condition        a radiation beam B (e.g. UV radiation or DUV radiation);    -   a support structure (e.g. a mask table) MT constructed to        support a patterning device (e.g. a mask) MA and connected to a        first positioner PM configured to accurately position the        patterning device MA in accordance with certain parameters;    -   a support table, e.g. a sensor table to support one or more        sensors or a substrate support apparatus 60 constructed to hold        a substrate (e.g. a resist-coated substrate) W, connected to a        second positioner PW configured to accurately position the        surface of the table, for example of a substrate W, in        accordance with certain parameters; and    -   a projection system (e.g. a refractive projection lens system)        PS configured to project a pattern imparted to the radiation        beam B by patterning device MA onto a target portion C (e.g.        comprising part of, one, or more dies) of the substrate W.

The illumination system IL may include various types of opticalcomponents, such as refractive, reflective, magnetic, electromagnetic,electrostatic or other types of optical components, or any combinationthereof, for directing, shaping, or controlling radiation.

The support structure MT holds the patterning device MA. It holds thepatterning device MA in a manner that depends on the orientation of thepatterning device MA, the design of the lithographic apparatus, andother conditions, such as for example whether or not the patterningdevice MA is held in a vacuum environment. The support structure MT canuse mechanical, vacuum, electrostatic or other clamping techniques tohold the patterning device MA. The support structure MT may be a frameor a table, for example, which may be fixed or movable as required. Thesupport structure MT may ensure that the patterning device MA is at adesired position, for example with respect to the projection system PS.Any use of the terms “reticle” or “mask” herein may be consideredsynonymous with the more general term “patterning device.”

The term “patterning device” used herein should be broadly interpretedas referring to any device that can be used to impart a radiation beamwith a pattern in its cross-section such as to create a pattern in atarget portion of the substrate. It should be noted that the patternimparted to the radiation beam may not exactly correspond to the desiredpattern in the target portion of the substrate, for example if thepattern includes phase-shifting features or so called assist features.Generally, the pattern imparted to the radiation beam will correspond toa particular functional layer in a device being created in the targetportion, such as an integrated circuit.

The patterning device MA may be transmissive or reflective. Examples ofpatterning devices include masks, programmable mirror arrays, andprogrammable LCD panels. Masks are well known in lithography, andinclude mask types such as binary, alternating phase-shift, andattenuated phase-shift, as well as various hybrid mask types. An exampleof a programmable mirror array employs a matrix arrangement of smallmirrors, each of which can be individually tilted so as to reflect anincoming radiation beam in different directions. The tilted mirrorsimpart a pattern in a radiation beam which is reflected by the mirrormatrix.

The term “projection system” used herein should be broadly interpretedas encompassing any type of projection system, including refractive,reflective, catadioptric, magnetic, electromagnetic and electrostaticoptical systems, or any combination thereof, as appropriate for theexposure radiation being used, or for other factors such as the use ofan immersion liquid or the use of a vacuum. Any use of the term“projection lens” herein may be considered as synonymous with the moregeneral term “projection system”.

As here depicted, the apparatus is of a transmissive type (e.g.employing a transmissive mask). Alternatively, the apparatus may be of areflective type (e.g. employing a programmable mirror array of a type asreferred to above, or employing a reflective mask).

The lithographic apparatus may be of a type having two or more tables(or stage(s) or support(s)), e.g., two or more substrate tables or acombination of one or more substrate tables and one or more sensor ormeasurement tables. In such “multiple stage” machines the multipletables may be used in parallel, or preparatory steps may be carried outon one or more tables while one or more other tables are being used forexposure. The lithographic apparatus may have two or more patterningdevice tables (or stage(s) or support(s)) which may be used in parallelin a similar manner to substrate, sensor and measurement tables.

Referring to FIG. 1, the illuminator IL receives a radiation beam from aradiation source SO. The source SO and the lithographic apparatus may beseparate entities, for example when the source SO is an excimer laser.In such cases, the source SO is not considered to form part of thelithographic apparatus and the radiation beam is passed from the sourceSO to the illuminator IL with the aid of a beam delivery system BDcomprising, for example, suitable directing mirrors and/or a beamexpander. In other cases the source SO may be an integral part of thelithographic apparatus, for example when the source SO is a mercurylamp. The source SO and the illuminator IL, together with the beamdelivery system BD if required, may be referred to as a radiationsystem.

The illuminator IL may comprise an adjuster AD for adjusting the angularintensity distribution of the radiation beam. Generally, at least theouter and/or inner radial extent (commonly referred to as σ-outer andσ-inner, respectively) of the intensity distribution in a pupil plane ofthe illuminator IL can be adjusted. In addition, the illuminator IL maycomprise various other components, such as an integrator IN and acondenser CO. The illuminator IL may be used to condition the radiationbeam to have a desired uniformity and intensity distribution in itscross-section. Similar to the source SO, the illuminator IL may or maynot be considered to form part of the lithographic apparatus. Forexample, the illuminator IL may be an integral part of the lithographicapparatus or may be a separate entity from the lithographic apparatus.In the latter case, the lithographic apparatus may be configured toallow the illuminator IL to be mounted thereon. Optionally, theilluminator IL is detachable and may be separately provided (forexample, by the lithographic apparatus manufacturer or anothersupplier).

The radiation beam B is incident on the patterning device (e.g., mask)MA, which is held on the support structure (e.g., mask table) MT, and ispatterned by the patterning device MA. Having traversed the patterningdevice MA, the radiation beam B passes through the projection system PS,which focuses the beam onto a target portion C of the substrate W. Withthe aid of the second positioner PW and position sensor IF (e.g. aninterferometric device, linear encoder or capacitive sensor), thesubstrate support apparatus 60 can be moved accurately, e.g. so as toposition different target portions C in the path of the radiation beamB. Similarly, the first positioner PM and another position sensor (whichis not explicitly depicted in FIG. 1) can be used to accurately positionthe patterning device MA with respect to the path of the radiation beamB, e.g. after mechanical retrieval from a mask library, or during ascan. In general, movement of the support structure MT may be realizedwith the aid of a long-stroke module (coarse positioning) and ashort-stroke module (fine positioning), which form part of the firstpositioner PM. Similarly, movement of the substrate support apparatus 60may be realized using a long-stroke module and a short-stroke module,which form part of the second positioner PW. In the case of a stepper(as opposed to a scanner) the support structure MT may be connected to ashort-stroke actuator only, or may be fixed. Patterning device MA andsubstrate W may be aligned using patterning device alignment marks M1,M2 and substrate alignment marks P1, P2. Although the substratealignment marks as illustrated occupy dedicated target portions, theymay be located in spaces between target portions C (these are known asscribe-lane alignment marks). Similarly, in situations in which morethan one die is provided on the patterning device MA, the patterningdevice alignment marks may be located between the dies.

The depicted apparatus could be used in at least one of the followingmodes:

1. In step mode, the support structure MT and the substrate supportapparatus 60 are kept essentially stationary, while an entire patternimparted to the radiation beam B is projected onto a target portion C atone time (i.e. a single static exposure). The substrate supportapparatus 60 is then shifted in the X and/or Y direction so that adifferent target portion C can be exposed. In step mode, the maximumsize of the exposure field limits the size of the target portion Cimaged in a single static exposure.

2. In scan mode, the support structure MT and the substrate supportapparatus 60 are scanned synchronously while a pattern imparted to theradiation beam B is projected onto a target portion C (i.e. a singledynamic exposure). The velocity and direction of the substrate supportapparatus 60 relative to the support structure MT may be determined bythe (de-)magnification and image reversal characteristics of theprojection system PS. In scan mode, the maximum size of the exposurefield limits the width (in the non-scanning direction) of the targetportion C in a single dynamic exposure, whereas the length of thescanning motion (and size of the exposure field) determines the height(in the scanning direction) of the target portion C.

3. In another mode, the support structure MT is kept essentiallystationary holding a programmable patterning device, and the substratesupport apparatus 60 is moved or scanned while a pattern imparted to theradiation beam is projected onto a target portion C. In this mode,generally a pulsed radiation source is employed and the programmablepatterning device is updated as required after each movement of thesubstrate support apparatus 60 or in between successive radiation pulsesduring a scan. This mode of operation can be readily applied to masklesslithography that utilizes a programmable patterning device, such as aprogrammable mirror array of a type as referred to above.

Combinations and/or variations on the above described modes of use orentirely different modes of use may also be employed.

Arrangements for providing liquid between a final element of theprojection system PS and the substrate can be classed into three generalcategories. These are the bath type arrangement, the so-called localizedimmersion system and the all-wet immersion system. In a bath typearrangement substantially the whole of the substrate W and optionallypart of the substrate support apparatus 60 is submersed in a bath ofliquid.

A localized immersion system uses a liquid supply system in which liquidis only provided to a localized area of the substrate. The space filledby liquid is smaller in plan than the top surface of the substrate andthe volume filled with liquid remains substantially stationary relativeto the projection system PS while the substrate W moves underneath thatvolume. FIGS. 2-5 show different supply devices which can be used insuch a system. A sealing feature is present to seal liquid to thelocalized area. One way which has been proposed to arrange for this isdisclosed in PCT patent application publication no. WO 99/49504.

In an all wet arrangement the liquid is unconfined. The whole topsurface of the substrate and all or part of the substrate table iscovered in immersion liquid. The depth of the liquid covering at leastthe substrate is small. The liquid may be a film, such as a thin film,of liquid on the substrate. Immersion liquid may be supplied to or inthe region of a projection system and a facing surface facing theprojection system (such a facing surface may be the surface of asubstrate and/or a substrate table). Any of the liquid supply devices ofFIGS. 2-5 can also be used in such a system. However, a sealing featureis not present, not activated, not as efficient as normal or otherwiseineffective to seal liquid to only the localized area.

As illustrated in FIGS. 2 and 3, liquid is supplied by at least oneinlet onto the substrate, preferably along the direction of movement ofthe substrate relative to the final element. Liquid is removed by atleast one outlet after having passed under the projection system. As thesubstrate is scanned beneath the element in a −X direction, liquid issupplied at the +X side of the element and taken up at the −X side.Various orientations and numbers of in- and outlets positioned aroundthe final element are possible; one example is illustrated in FIG. 3 inwhich four sets of an inlet with an outlet on either side are providedin a regular pattern around the final element. Note that the directionof flow of the liquid is shown by arrows in FIGS. 2 and 3.

A further immersion lithography solution with a localized liquid supplysystem is shown in FIG. 4. Liquid is supplied by two groove inlets oneither side of the projection system PS and is removed by a plurality ofdiscrete outlets arranged radially outwardly of the inlets. Note thatthe direction of flow of fluid and of the substrate is shown by arrowsin FIG. 4.

Another arrangement which has been proposed is to provide the liquidsupply system with a liquid confinement structure which extends along atleast a part of a boundary of the space between the final element of theprojection system and the substrate, substrate table or both. Such anarrangement is illustrated in FIG. 5.

FIG. 5 schematically depicts a localized liquid supply system or fluidhandling system with a liquid confinement structure IH, which extendsalong at least a part of a boundary of the space between the finalelement of the projection system and the substrate support apparatus 60or substrate W. (Please note that reference in the following text tosurface of the substrate W also refers in addition or in the alternativeto a surface of the substrate table, unless expressly stated otherwise.)In an embodiment, a seal is formed between the liquid confinementstructure IH and the surface of the substrate W and which may be acontactless seal such as a gas seal (such a system with a gas seal isdisclosed in European patent application publication no. EP-A-1,420,298)or a liquid seal.

The liquid confinement structure IH at least partly contains liquid inthe space 11 between a final element of the projection system PS and thesubstrate W. The space 11 is at least partly formed by the liquidconfinement structure IH positioned below and surrounding the finalelement of the projection system PS. Liquid is brought into the spacebelow the projection system PS and within the liquid confinementstructure IH by liquid inlet 13. The liquid may be removed by liquidoutlet 13.

The liquid may be contained in the space 11 by a gas seal 16 which,during use, is formed between the bottom of the barrier member IH andthe surface of the substrate W. The gas in the gas seal is providedunder pressure via inlet 15 to the gap between barrier member IH andsubstrate W. The gas is extracted via outlet 14. The overpressure on thegas inlet 15, vacuum level on the outlet 14 and geometry of the gap arearranged so that there is a high-velocity gas flow 16 inwardly thatconfines the liquid. The force of the gas on the liquid between thebarrier member IH and the substrate W contains the liquid in a space 11.Such a system is disclosed in United States patent applicationpublication no. US 2004-0207824, which is hereby incorporated byreference in its entirety. In an embodiment, the liquid confinementstructure IH does not have a gas seal.

An embodiment of the present invention may be applied to any fluidhandling structure including those disclosed, for example, in UnitedStates patent application publication nos. US 2006-0158627, US2006-0038968, US 2008-0212046, US 2009-0279060, US 2009-0279062, US2004-0207824, US 2010-0313974 and US 2012-0120376, the contents of allof which are hereby incorporated in their entirety by reference.

A controller 500 controls the overall operations of the lithographicapparatus and in particular performs an operation process describedfurther below. Controller 500 can be embodied as a suitably-programmedgeneral purpose computer comprising a central processing unit, volatileand non-volatile storage means, one or more input and output devicessuch as a keyboard and screen, one or more network connections and oneor more interfaces to the various parts of the lithographic apparatus.It will be appreciated that a one-to-one relationship betweencontrolling computer and lithographic apparatus is not necessary. In anembodiment of the invention one computer can control multiplelithographic apparatuses. In an embodiment of the invention, multiplenetworked computers can be used to control one lithographic apparatus.The controller 500 may also be configured to control one or moreassociated process devices and substrate handling devices in a lithocellor cluster of which the lithographic apparatus forms a part. Thecontroller 500 can also be configured to be subordinate to a supervisorycontrol system of a lithocell or cluster and/or an overall controlsystem of a fab. In an embodiment the controller operates the apparatusto perform an embodiment of the present invention. In an embodiment thecontroller 500 has a memory to store the results of a step one describedherein for later use in a step two.

FIG. 6 depicts an embodiment of the present invention. FIG. 6 is across-section through a support apparatus and an object. In anembodiment the support apparatus is a substrate support apparatus 60 andthe object is a substrate W. The support apparatus comprises an objectholder. The object holder is configured to hold an object. In thedescription below, an embodiment of the invention is described in thecontext of the support apparatus being a substrate support apparatus 60and the object holder being a substrate holder 61 to hold a substrate W.However, in an embodiment, the object holder is, for example, a sensorholder to hold a sensor and the substrate support apparatus 60 is asupport apparatus for the object holder, optionally without being ableto hold a substrate.

As depicted in FIG. 6, the substrate W is held by the substrate holder61. In an embodiment, the substrate holder 61 comprises one or moreprojections 62 (e.g., burls). The substrate holder 61 may be termed apimple table or a burl table.

The substrate support apparatus 60 comprises an extraction body 65. Theextraction body 65 is radially outward of the substrate holder 61. InFIG. 6, the arrow below the drawing of the substrate support apparatus60 and the substrate W indicates the radially outward direction. In anembodiment, the extraction body 65 is shaped such that the extractionbody 65 surrounds, in plan view, the substrate holder 61. In anembodiment, the extraction body 65 forms a closed shape. The shape isnot particularly limited and may be an annulus or a polygon, forexample.

When the edge of the substrate W is being imaged or at other times suchas when the substrate W first moves under the projection system PS, theliquid 11 will pass at least partly over a gap 5 between the edge of thesubstrate W and the edge of the substrate support apparatus 60. This canresult in liquid from the liquid reservoir 11 entering the gap 5.

An under pressure applied between the substrate W and the substratesupport apparatus 60 by the substrate holder 61 helps ensure that thesubstrate W is held firmly in place. However, if liquid gets between thesubstrate W and the substrate holder 61 this can lead to difficulties,particularly when unloading the substrate W.

The extraction body 65 is configured to extract fluid from a top surface69 of the substrate support apparatus 60. By providing an extractionopening 66, there is a reduction in the bubbles of gas that enter theliquid 11 of the liquid supply system IH. One or more of such bubblescan deleteriously affect the imaging of the substrate W. The extractionopening 66 is provided to reduce gas in the gap 5, between the substrateW and the substrate support apparatus 60, escaping into the liquidreservoir 11 in the fluid handling structure IH. If gas does escape intothe liquid reservoir 11, this can lead to a bubble which floats withinthe liquid reservoir 11. Such a bubble, if in the path of the projectionbeam, can lead to imaging errors. The extraction opening 66 is to removegas from the gap 5 between the edge of the substrate W and the edge ofthe recess in the substrate support apparatus 60 in which the substrateW is placed.

The extraction opening 66 extracts mostly gas (say between 20 and 100normal liters per minute (Nl/min)) and only a small amount of immersionliquid (say about 1 to 100 ml/min, and optionally 10 to 20 ml/min). Withsuch a two-phase flow, the immersion liquid evaporates, cooling down thesubstrate support apparatus 60 surrounding the edge of the substrate W.This can result in deformation of the substrate W, which may eventuallylead to decreased overlay performance.

In an embodiment, the extraction body 65 is spaced from the substrateholder 61 such that the extraction body 65 is substantially decoupledfrom the substrate holder 61. The extraction body 65 is substantiallythermally decoupled and/or substantially mechanically decoupled from thesubstrate holder 61. In an embodiment substantially the whole of thesubstrate holder 61 is spaced from substantially the whole of theextraction body 65.

By providing that the extraction body 65 is substantially decoupled fromthe substrate holder 61, a temperature load on the extraction body 65has reduced impact on the thermo-mechanical behavior of the substrateholder 61. In particular, the effect of cooling down of the extractionbody 65 on the substrate holder 61 is decreased. As mentioned above,such evaporative cooling can occur due to the two-phase flow through theextraction opening 66 of the extraction body 65. Accordingly, thestability of the temperature profile of the substrate holder 61 can beimproved.

In an embodiment the object holder is a sensor holder configured to holda sensor, and the extraction body is an edge seal member. In anembodiment the edge seal member comprises an extraction opening toextract immersion liquid which should find its way through the gapbetween the edge seal member and the sensor.

In an embodiment the object holder is a substrate table configured tohold a substrate, and the extraction body is a sensor holder. A sensoris placed next to the substrate. The sensor and the substrate aresupported by different supports. In an embodiment the sensor holdercomprises an extraction opening to extract immersion liquid which shouldfind its way through the gap between the substrate table and the sensor.

In an embodiment, the extraction body 65 comprises a channel 68. Thechannel 68 is in fluid communication with the extraction opening 66through a passageway 67. The extraction opening 66 may be provided atone or more discrete locations around the periphery (e.g.,circumference) of the edge of the substrate W. The extraction opening 66may, in plan, be slits or circular openings or any other shape. In anembodiment, three discrete circular openings are provided to extract atwo-phase flow from the extraction body 65 to the substrate supportapparatus 60. An extraction opening 66 may have a diameter of 2 mm. Thechannel 68 is connected to an under pressure so as to extract fluidthrough the opening 66 from the top surface 69 of the substrate supportapparatus 60.

In an embodiment, the extraction body 65 has no connection to thesubstrate holder 61 such that the extraction body 65 is detached fromthe substrate holder 61. The extraction body 65 is not in direct contactwith the substrate holder 61 at any point. This reduces heat transferbetween the extraction body 65 and the substrate holder 61, particularlyheat transfer by conduction. In an embodiment the gap 5, between thesubstrate W and the substrate support apparatus 60, is narrow such thatliquid loss through the gap 5 to the bottom of the substrate holder 61is minimal.

In an embodiment, the extraction body 65 is connected to the substrateholder 61. FIG. 7 depicts such an embodiment of the present invention.The extraction body 65 is substantially decoupled from the substrateholder 61. The extraction body 65 is non-rigidly connected to thesubstrate holder 61 by a seal. The seal is configured to bridge anintermediate gap 75 between the extraction body 65 and the substrateholder 61.

In an embodiment the seal comprises a sticker 70. The sticker 70 isarranged to reduce liquid loss through the intermediate gap 75. In anembodiment, the sticker 70 seals the intermediate gap 75. In anembodiment the seal is formed by welding, bolting or vacuum clamping,for example. The extraction opening 66 is configured to extract fluidfrom the gap, above the seal, between the substrate holder 61 and theextraction body 65.

In an embodiment, the sticker 70 comprises an adhesive layer 71 and afilm layer 72. The adhesive layer 71 adheres the film layer 72 to thesubstrate holder 61 and to the extraction body 65. The sticker 70 helpsprevent fluid from entering the intermediate gap 75 between thesubstrate holder 61 and the extraction body 65. The intermediate gap 75prevents a good thermal contact between the substrate holder 61 and theextraction body 65. In an embodiment, the sticker 70 has a thickness ofless than or equal to 50 micrometers, less than or equal 10 micrometers,or about 10 micrometers.

In an embodiment, the extraction body 65 is spaced from the substrateholder 61 by an intermediate gap 75 that comprises a vacuum or a gas. Avacuum, or near vacuum, in the intermediate gap 75 reduces the thermaltransfer between the extraction body 65 and the substrate holder 61.

FIG. 8 depicts an embodiment of the present invention. As depicted inFIG. 8, in an embodiment the substrate support apparatus 60 comprises asubstrate table WT. The substrate holder 61 is positioned within anobject holder recess of the substrate table WT. In the context of theobject holder being a substrate holder 61, the object holder recess is asubstrate holder recess 85 of the substrate table WT. At least part ofthe extraction body 65 is positioned within the substrate holder recess85. As depicted in FIG. 8, in an embodiment substantially all of theextraction body 65 is positioned within the substrate holder recess 85.However, this need not necessarily be the case. As will be explainedbelow, and as depicted in FIG. 12 for example, in an embodiment part ofthe extraction body 65 extends beyond the substrate holder recess 85.

As depicted in FIG. 8, the extraction body 65 is connected to thesubstrate table WT at an interface 81. The interface 81 provides aconnection between the extraction body 65 and the substrate table WT.Acceleration forces of the substrate WT are transferred to theextraction body 65 via the interface 81. The interface 81 provides astiff connection to the extent that the interface 81 transfersaccelerating forces from the substrate table WT to the extraction body65. The stiffness of the connection at the interface 81 is desirablyminimal so as to reduce thermal transfer between the extraction body 65and the substrate table WT.

In an embodiment, the interface 81 is at a bottom surface 82 and/or aradial surface (e.g. a radially outward edge) of the extraction body 65.This is depicted in FIG. 8. In an embodiment, the interface 81 is at anouter surface of the extraction body 65.

The form of connection at the interface 81 is not particularly limited.In an embodiment, the extraction body 65 is connected to the substratetable WT by vacuum clamping, bolting, gluing, and/or kinematic leafspring coupling.

In an embodiment, the interface 81 comprises one or more burls. In anembodiment the connection area between the burl and the substrate tableWT is smaller than the contact surface between the burl and theextraction body 65. This provides the burl with extra flexibility.

In an embodiment, the surfaces of the gap 5 are provided with ahydrophobic coating. The hydrophobic coating helps to reduce the loss ofliquid from the top surface 69 of the substrate support apparatus 60through the intermediate gap 75.

In an embodiment, the extraction body 65 is made of the same material asthe substrate holder 61. In an embodiment, both the substrate holder 61and the extraction body 65 are formed of SiC, SiSiC, or a diamond-likematerial, for example. By matching the material of the extraction body65 with the material of the substrate holder 61, thermo-mechanicalcross-talk between the substrate holder 61 and the extraction body 65can be reduced.

In an embodiment, the extraction body 65 is made from the same materialas the substrate table WT. In an embodiment, both the extraction body 65and the substrate table WT are formed from a glass-ceramic, such asZerodur®, or cordierite, for example.

FIG. 9 depicts, in plan view, an embodiment of the present invention. Inan embodiment, the extraction body 65 is connected to the substrateholder 61 by a plurality of peripherally spaced joints 91. Between thejoints 91, the extraction body 65 is spaced from the substrate holder61.

By providing that the extraction body 65 is connected to the substrateholder 61 only by the joints 91, the heat transfer between the substrateholder 61 and the extraction body 65 is reduced. This reduces the effectof evaporative cooling at the extraction body 65 on the substrate holder61. In turn, this reduces the effects of the evaporative cooling on thesubstrate W. The stability of the thermal profile of the substrateholder 61 is improved.

Gaps 92 are formed between the joints 91. The gaps 92 may comprise avacuum or a gas. The gaps 92 reduce the heat transfer between theextraction body 65 and the substrate holder 61 particularly heattransfer by conduction. In an embodiment, surfaces of the gaps 92 areprovided with a hydrophobic coating.

The joints 91 provide a minimally stiff connection between theextraction body 65 and the substrate holder 61. The connection may bestiff enough such that acceleration forces are transferred from thesubstrate holder 61 to the extraction body 65. In an embodiment, thestiffness is minimal so as to reduce thermo-mechanical cross-talkbetween the substrate holder 61 and the extraction body 65.

As depicted in FIGS. 8 and 12, for example, in an embodiment, thesubstrate holder 61 is connected to the substrate table WT by a seriesof burls, for example. The burls allow acceleration forces to betransferred from the substrate table WT to the substrate holder 61,while also providing gaps between the burls that reduce thermal transferbetween the substrate table WT and the substrate holder 61.

FIG. 10 depicts an embodiment of the present invention. In anembodiment, at least one of the joints 91 extends from a top surface ofthe substrate holder 61 only partially towards a bottom surface 82 ofthe extraction body 65. Directly below at least one of the joints 91,the extraction body 65 is spaced from the substrate holder 61. Below theat least one of the joints 91 a gap 106 is provided between thesubstrate holder 61 and the extraction body 65. The gap 106, which maycomprise a vacuum or a gas, reduces heat transfer between the substrateholder 61 and the extraction body 65. The gap 106 is in fluidcommunication with the gaps 92.

In an embodiment, the joints 91 extend from a top surface of thesubstrate holder 61 to a bottom surface 82 of the extraction body 65. Inan embodiment the joint 91 is monolithic with the substrate holder 61and/or the extraction body 65. In an embodiment the joint 91 is not aseparate piece from the substrate holder 61 and/or the extraction body65. In an embodiment the extraction opening 66 is positioned above thejoint 91.

In an embodiment, at least one of the joints 91 comprises a jointconditioning system 101 configured to supply heat energy to and/orremove heat energy from the joint 91 and/or between the joint 91. Thejoint conditioning system 101 may be any type of thermal conditioningsystem. Suitable thermal conditioning systems are described in furtherdetail below and are depicted in FIGS. 15 to 19. FIGS. 15 to 19 depictsuitable thermal conditioning systems applied to the main body of theextraction body 65. In particular, FIGS. 15 to 19 depict thermalconditioning systems applied to the channel 68 that is in fluidcommunication with the extraction opening 66. These thermal conditioningsystems may be applied to the joint 91.

In an embodiment, the joints 91, in total, extend along at most 10% of aperiphery between the substrate holder 61 and the extraction body 65.The periphery extends along the gaps 92 between the joints 91. At least90% of the periphery of the intermediate gap 75 between the substrateholder 61 and the extraction body 65 consists of the gaps 92 between thejoints 91. In FIG. 9, the intermediate gap 75 is represented as theregion between the two dashed lines. The two dashed lines correspond tothe edges of the substrate holder 61 and the extraction body 65. Byproviding that the joints 91 extend along at most 10% of the periphery,the thermal transfer between the subject holder 61 and the extractionbody 65 can be reduced to an acceptable level.

In an embodiment, the joints 91 provide mechanical stiffness between thesubstrate holder 61 and the extraction body 65. In an embodiment, thejoints 91, in total, extend along at least 2% or at least 5% of theperiphery. This allows the joints 91 to provide an acceptable level ofmechanical stiffness between the substrate holder 61 and the extractionbody 65.

The substrate support apparatus 60 depicted in FIGS. 9 and 10 may beprovided with a substrate table WT as depicted in FIG. 8, for example.

The number of joints 91 is not particularly limited. In an embodiment,the substrate support apparatus 60 comprises 6, 8, 10, 12, 14 or morejoints 91. The number of joints 91 may be odd or even. The extractionbody 65 is segmented into as many segments 93 as there are joints 91.Each segment 93 extends along the extraction body 65 from one joint 91to an adjacent joint 91. Each segment 93 is spaced from the substrateholder 61 by a gap 92.

The extraction body 65 is mechanically and thermally connected to thesubstrate holder 61 only by the joints 91. This reduces the thermalcross-talk from the extraction body 65 to the substrate holder 61. Thethermal conduction between the substrate holder 61 and the extractionbody 65 is reduced.

A variation in temperature of the extraction body 65 can result inmechanical stress being introduced at the outer edge of the substrateholder 61. This is due to mechanical cross-talk. This mechanicalcross-talk can result in local deformation of the substrate holder 61and the substrate W.

In the embodiment depicted in FIG. 9, the mechanical cross-talk betweenthe extraction body 65 and the substrate holder 61 acts differentlycompared to in a conventional system. In the segmented extraction body65, mechanical stress is transferred to the substrate holder 61 only atthe positions of the joints 91. The stress introduced in the substrateholder 61 is determined by the elongation (or contraction) of eachsegment 93 of the extraction body 65 as well as the stiffness of thejoints 91.

The elongation of each segment 93 is influenced mainly by the averagetemperature of that segment 93. In order to reduce the elongation of asegment 93, the sum of all local strains within that segment 93 shoulddesirably be reduced to 0. In this case, there would be no mechanicalstress on the substrate holder 61. The term elongation above is used tomean the increase in length of a segment 93 due to variation intemperature. Contraction of the segment 93 due to variation intemperature should also be desirably reduced.

In an embodiment, at least one of the segments 93 comprises a resistivesensor 94. The resistive sensor 94 may be a thin film resistive sensor.The resistive sensor 94 is configured to measure the average temperatureof the segment 93. The resistive sensor 94 is positioned on or at asurface of the extraction body 65. For example, the resistive sensor 94may be positioned on or at a top surface 105 or on or at a bottomsurface 82 of the extraction body 65.

In an embodiment, at least one of the segments 93 comprises a heaterconfigured to apply heat energy to the extraction body 65. In anembodiment, the controller 500 is configured to control the heater basedon the measurements by the resistive sensor 94 so as to maintain theaverage temperature of the segment 93. In an embodiment, the resistivesensor 94 is used to apply heat to the extraction body 65. This can bedone, for example, applying a current to the resistive sensor 94. Inthis case there is no need for an additional heater.

The resistive sensor 94 measures the electrical resistance oversubstantially the whole length of the resistive sensor 94. In anembodiment, the resistive sensor 94 is positioned between two adjacentjoints 91. The resistive sensor 94 measures the average temperature ofthat segment 93. The average temperature of the segment 93 correspondsto the elongation (or contraction) of the segment 93.

The thermal response of the resistive sensor 94 is very fast because ofits low mass. The control performance can be increased by using theresistive sensor 94, and optionally a separate heater, compared to usingconventional sensors and flex foil heaters, for example. In anembodiment the resistive sensor 94 is replaced with a thin film heater.

In an embodiment, the gaps 92 comprise a vacuum. In an embodiment, thegaps 92 are open at the upper surface of the substrate support apparatus60. However, this need not necessarily be the case. In an embodiment,the gaps 92 may be covered or closed. For example, a thin filmmaterial/seal such as a sticker may be applied over the gaps 92, or thegaps 92 may be closed with a material that has low thermal conductivity.

FIG. 11 depicts an embodiment of the present invention. In anembodiment, the extraction body 65 comprises a main body 111 and a coverring 112. The cover ring 112 is positioned at a top surface 115 of themain body 111. In an embodiment, the cover ring 112 is monolithic withthe main body 111. In an embodiment, the cover ring 112 is a separatebody from the main body 111. By providing the cover ring 112 at the topof the extraction body 65 that would come into contact with the liquidsupply device IH in normal use, a thermal load in the extraction opening66, passageway 67 and channel 68 have a reduced thermal effect on theliquid supply device IH.

FIG. 12 depicts an embodiment of the present invention. In anembodiment, the cover ring 112 extends radially outwards beyond a radialextent of the main body 111. The extraction body 65 has a steppedprofile when viewed in cross-section.

By providing that the cover ring 112 extends radially outward beyond aradial extent of the main body 111, less of the top surface 122 of thesubstrate table WT comes into contact with the liquid reservoir 11 inuse of the lithographic apparatus. In an embodiment, the top surface 122of the substrate table WT is provided with a hydrophobic coating. Thehydrophobic coating helps to reduce the evaporation load on thesubstrate table WT. When the liquid reservoir 11 comes into contact withthe top surface 122 of the substrate table WT, the hydrophobic coatingcan degrade. This can result in an increase in liquid loss and anincreased evaporation load. The evaporation load can result indeformation of the substrate table WT.

The cover ring 112 can protect part of the substrate table WT. When theliquid reservoir 11 comes into contact with the cover ring 112, there isan evaporation load generated on the cover ring 112 (and a correspondingreduction in evaporation load on the top surface 122 of the substratetable WT). The thermal load due to the fluid handling structure IH has areduced effect on the substrate table WT. This improves the stability ofthe temperature profile of the substrate table WT.

In an embodiment, a part of the cover ring 112 that extends radiallyoutward beyond the radial extent of the main body 111 is positionedwithin a cover ring recess 125 of the substrate table WT. In anembodiment, the cover ring recess 125 is radially outward of thesubstrate holder recess 85. The cover ring recess 125 is shallower thanthe substrate holder recess 85 such that the cover ring recess 125 andthe substrate holder recess 85 form stepped recesses of the substratetable WT.

In an embodiment, when the substrate W is held by the substrate holder61, the top surface of the substrate W is substantially coplanar withthe top surface 105 of the extraction body 65. In an embodiment, the topsurface 105 of the extraction body 65 is substantially coplanar with thetop surface 122 of the substrate table WT.

In an embodiment, the cover ring 112 extends substantially to afiduciary marker 121 at a top surface 122 of the substrate table WT.However, this need not necessarily be the case. In an embodiment, thefiduciary marker 121 is spaced from the cover ring recess 125 of thesubstrate table WT.

In an embodiment, a gap 123 between the cover ring 112 and the fiduciarymarker 121 (or the top surface 122) at the top surface 122 of thesubstrate table WT is bridged by a thin film seal 124. The thin filmseal 124 comes in various constructions, which may be the same as thevarious possible constructions of the sticker 70 described in relationto FIG. 7.

By providing that the cover ring 112 extends over a part of thesubstrate table WT that would normally come into contact with the liquidsupply device IH, a thermal load in the substrate table WT has a reducedeffect on the liquid supply device IH and in particular on the liquidlens of the lithographic apparatus. This improves overlay and focus ofthe lithographic apparatus. In an embodiment the cover ring 112 isthermally conditioned in a similar way to joints 91. In an embodimentthe cover ring 112 is arranged so as to provide a thermal shield againstpossible sources of heating and/or cooling of the substrate table WT.This may be achieved by providing thermal insulation between the coverring 112 and the substrate table WT.

In an embodiment, the cover ring 112 has a thickness of at least 3 mm.In an embodiment, the cover ring 112 has a thickness so as to be stiffsuch that there is substantially no contact needed between the bottom ofthe cover ring 112 and the surface of the substrate table WT that isdirectly below the cover ring 112 in use of the lithographic apparatus.However, in an embodiment, a non-rigid local connection is providedbetween the bottom surface of the cover ring 112 and the opposingsurface of the substrate table WT. In an embodiment, the non-rigid localconnection has very low thermal conductivity so as to reduce thermaltransfer between the substrate table WT and the cover ring 112 of theextraction body 65.

FIG. 13 depicts an embodiment of the present invention. In anembodiment, the substrate support apparatus 60 comprises a liquidextractor 130. The liquid extractor 130 is radially inward of theextraction opening 66. The liquid extractor 130 is configured to extractliquid from a top surface of the substrate holder 61.

The liquid extractor 130 is provided to help prevent any liquid whichfinds its way from the gap 5 to underneath the substrate W frompreventing efficient release of the substrate W from the substrateholder 61 after imaging. The provision of the liquid extractor 130reduces or eliminates a problem which may occur due to liquid findingits way underneath the substrate W. The liquid extractor 130, like theextraction opening 66, removes fluid by way of an under pressure.

The liquid extractor 130 comprises an opening 131 and a channel 133. Thechannel 133 is in fluid communication with the opening 131 through apassageway 132. The opening 131 may be provided at one or more discretelocations around the periphery of the edge of the substrate W and may,in plan, be slits or circular openings or any other shape. In anembodiment, three discrete (circular) openings 131 are provided aroundthe edge of the substrate W, for instance.

FIG. 14 depicts an embodiment of the present invention. In anembodiment, the extraction body 65 comprises at least part of the liquidextractor 130. In an embodiment, the channel 133 is provided in theextraction body 65. In an embodiment, the passageway 132 spans theintermediate gap 75 between the extraction body 65 and the substrateholder 61. In an embodiment the intermediate gap 75 is narrow such thatliquid loss to the bottom of the substrate holder 61 is minimal.

By providing at least part of the liquid extractor 130 in the extractionbody 65, the thermal load at the liquid extractor 130 has a reducedeffect on the substrate holder 61.

In an embodiment, the liquid extractor 130 comprises a liquid extractorconditioning system configured to supply heat energy to and/or removeheat energy from the liquid extractor 130. The liquid extractorconditioning system is a thermal conditioning system. Suitable thermalconditioning systems are described below and depicted in FIGS. 15 to 19.In FIGS. 15 to 19, thermal conditioning systems are depicted in thecontext of thermal conditioning systems for the channel 68 in fluidcommunication with the extraction opening 66 of the extraction body 65.These thermal conditioning systems are equally applicable to the liquidextractor 130, and in particular to the channel 133 of the liquidextractor 130.

In an embodiment, the extraction body 65 is positioned between thesubstrate holder 61 and the substrate table WT. In an embodiment, theextraction opening 66 is configured to extract both a gas and a liquidfrom a top surface 69 of the substrate support apparatus 60. In anembodiment, a space between the extraction body 65 and the substrateholder 61 is continuous peripherally and continuous from a top surface105 of the extraction body 65 to a bottom surface 82 of the extractionbody 65.

FIGS. 15 to 19 depict thermal conditioning systems according to anembodiment of the present invention. In FIGS. 15 to 19, the thermalconditioning systems are applied to parts of the extractor of theextraction body 65. The thermal conditioning systems can be applied tothe liquid extractor 130 and/or to the joints 91 and/or to other partsof the substrate support apparatus 60. The thermal conditioning systemsdepicted in FIGS. 15 to 19 may be combined with each other.

In an embodiment, the extraction body 65 comprises an extraction bodyconditioning system configured to supply heat energy to and/or removeheat energy from the extraction body 65. The extraction bodyconditioning system is a thermal conditioning system.

FIG. 15 depicts a thermal conditioning system according to an embodimentof the present invention. In an embodiment, the thermal conditioningsystem comprises a plurality of conditioning units that areindependently controllable. Each of the plurality of conditioning unitsis configured to supply heat energy to and/or remove heat energy from arespective conditioning region of the extraction body 65. In anembodiment, a conditioning unit comprises a heater/temperature sensor151. In an embodiment, the heater/temperature sensors are positionedadjacent to the channel 68 that is in fluid communication with theextraction opening 66 of the extraction body 65.

The heater/temperature sensors 151 are independently controllable. Thetemperature sensor is configured to sense the temperature of the channel68. The heater is configured to supply heat energy to the channel 68. Inan embodiment, the controller 500 controls the heater/temperaturesensors 151 so as to maintain the channel 68 (or another component ofthe substrate support apparatus 60) at a certain (e.g., predetermined)temperature.

FIG. 16 depicts a thermal conditioning system according to an embodimentof the present invention. In an embodiment, the thermal conditioningsystem comprises a network of fluid-carrying channels 161 configured tocontrol the temperature of the component, such as the extraction body 65in the depiction of FIG. 16. In an embodiment, the fluid-carryingchannels 161 carry a thermal conditioning liquid. The thermalconditioning liquid may be water, for example. The fluid-carryingchannels 161 maintain the temperature of the extraction body 65 at acertain (e.g., predetermined) temperature. In an embodiment, one or moreheater/temperature sensors (not shown) may be positioned in or near thefluid-carrying channels 161 so as to control the temperature of thethermal conditioning liquid within the fluid-carrying channels 161.

In an embodiment the fluid-carrying channels 161 carry a phase changematerial. In such a system the phase change material is chosen such thatit changes phase at a desired set point temperature and is thereforecapable of transferring heat much more efficiently than a fluid whichdoes not change phase.

In an embodiment, the fluid-carrying channels 161 carry carbon dioxideas the fluid. The fluid-carrying channels 161 may be termed coolingchannels. In an embodiment, the fluid-carrying channels 161 containcarbon dioxide at a pressure such that the carbon dioxide has a boilingpoint of at most 30° C., and optionally at most 22° C. The carbondioxide helps maintain the temperature of the extraction body 65. Forexample, excess heat in the extraction body 65 above the boiling pointof the carbon dioxide contained in the fluid-carrying channels 161 canbe transferred to the carbon dioxide. This excess heat causes the carbondioxide to boil.

FIG. 17 depicts a thermal conditioning system according to an embodimentof the present invention. In an embodiment, the thermal conditioningsystem comprises a heat pipe 171. In an embodiment, the heat pipe 171 ispositioned around the channel 68. By providing a heat pipe 171 aroundthe channel 68, the temperature of the channel 68 can be easilycontrolled. This is due to the fact that a heat pipe 171 has a verylarge “conductivity”.

In an embodiment, at least a part of the heat pipe 171 is positionedbetween the channel 68 and the substrate holder 61. This reduces thetransfer of heat between the extraction body 65 and the substrate holder61. The temperature of the heat pipe 171 is very homogeneous due to thehomogeneous pressure within the heat pipe 171. The heat pipe 171contains a working fluid that can evaporate to vapor, thereby absorbingthermal energy. The vapor migrates along the cavity of the heat pipe 171to a region at a lower temperature. The vapor then condenses back intothe working fluid and is absorbed by a wick in the heat pipe 171. Thiscondensation releases thermal energy. The working fluid then flows backto a higher temperature region of the heat pipe 171. In this way, thetemperature of the heat pipe 171 remains substantially homogeneous.

In an embodiment, the heat pipe 171 comprises a working fluid selectedfrom the group consisting of water, acetone, ethanol, methanol, ammonia,2-butane, DME, 1,1,1,2-tetrafluoroethane and propane. Other workingfluids may be suitable.

FIG. 19 depicts a thermal conditioning system according to an embodimentof the present invention. As depicted in FIG. 19, the thermalconditioning system may comprise a heat pipe 171 and at least oneheater/temperature sensor 151. The heater/temperature sensor isconfigured to apply energy to the heat pipe 171. This sets thesaturation pressure for the working fluid in the heat pipe 171.

FIG. 18 depicts a thermal conditioning system according to an embodimentof the present invention. In the embodiment depicted FIG. 18, theheater/temperature sensors 151 are combined with the fluid-carryingchannels 161. In an embodiment, the thermal conditioning system isprovided within the extraction body 65 around the channel 68. In anembodiment, the controller 500 controls the thermal energy provided bythe heater/temperature sensor 151 to the channel 68.

The energy provided to the heater/temperature sensor 151 may beelectrical. The heater/temperature sensor 151 converts the electricalenergy into heat energy. If the electrical energy provided to theheater/temperature sensor 151 is too low, then the thermal energyprovided by the heater/temperature sensor 151 will be too low. If theelectrical energy provided to the heater/temperature sensor 151 is toohigh, then the thermal energy provided by the heater/temperature sensor151 will be too high. This can lead to the temperature of the extractionbody 65 being too low or too high. By providing that theheater/temperature sensors 151 are independently controllable, thispotential error can be reduced.

By providing additionally the network of fluid-carrying channels 161,the stability of the temperature of the extraction body 65 can beimproved. If there is excess heat provided by the heater/temperaturesensors 151, then the excess heat will be absorbed by the evaporation ofthe carbon dioxide, for example, contained within the fluid-carryingchannels 161.

In an embodiment, the controller 500 is configured to control thepressure of the carbon dioxide within the fluid-carrying channels 161 tobe about 6×10⁶ Pa. Another fluid instead of or in addition to carbondioxide may be used in the fluid-carrying channels 161.

FIG. 20 depicts an embodiment of the present invention. In anembodiment, the extraction body 65 comprises an edge heater 201 on anouter edge of the extraction body 65. In an embodiment, the extractionbody 65 comprises an edge heater 202 on an inner surface of theextraction body 65. In an embodiment, the substrate holder 61 comprisesan edge heater 203 positioned at an outer edge of the substrate holder61. In an embodiment, the edge heaters 201, 202, 203 are independentlycontrollable by the controller 500. The edge heaters 201, 202, 203 helpmaintain stability of the temperature profile of the substrate supportapparatus 60. Each of the edge heaters 201, 202, 203 may comprise atemperature sensor.

FIGS. 21 to 26 depict specific embodiments of the invention formed bycombining feature described above. Further specific embodiments may beformed by other combinations of the possible features described herein.

FIG. 21 depicts an embodiment of the present invention. In theembodiment depicted in FIG. 21, the liquid extractor 130 is provided inthe substrate holder 61. The substrate holder 61 is thermallyconditioned by a network of fluid-carrying channels 161. The extractionbody 65 is thermally conditioned by a network of fluid-carrying channels161. The cover ring 112 of the extraction body 65 is thermallyconditioned by a fluid-carrying channel 161.

FIG. 22 depicts an embodiment of the present invention. In theembodiment depicted in FIG. 22, the liquid extractor 130 is provided inthe substrate holder 61. The substrate holder 61 comprises a network offluid-carrying channels 161 configured to control the temperature of thesubstrate holder 61. The substrate holder 61 comprises an edge heater203 positioned at an outer edge of the substrate holder 61. Theextraction body 61 comprises edge heaters 201, 202 at the outer edge andthe inner edge of the extraction body 65.

FIG. 23 depicts an embodiment of the present invention. In theembodiment depicted in FIG. 23, the liquid extractor 130 is provided inthe substrate holder 61. The substrate holder 61 is thermallyconditioned by a network of fluid-carrying channels 161. The extractionbody 65 comprises edge heaters 201, 202 at the outer edge and the inneredge of the extraction body 65.

FIG. 24 depicts an embodiment of the present invention. In theembodiment depicted in FIG. 24, part of the liquid extractor 130 isprovided in the extraction body 65. The channel 133 is provided in theextraction body 65. Part of the passageway 132 is provided in theextraction body 65. The substrate holder 61 comprises a network offluid-carrying channels 161 configured to control the temperature of thesubstrate holder 61. The extraction body 65 comprises edge heaters 201,202 at the outer edge and the inner edge of the extraction body 65. Theedge heaters 201, 202 are configured to control the temperature of theextraction body 65. The embodiment depicted in FIG. 24 may be modifiedby replacing the edge heater 201, 202 with fluid-carrying channels 161.

FIG. 25 depicts an embodiment of the present invention. In theembodiment depicted in FIG. 25, part of the liquid extractor 130 isprovided in the extraction body 65. The channel 133 is provided in theextraction body 65. Part of the passageway 132 is provided in theextraction body 65. The extraction body 65 has a stepped shape thatcorresponds to a stepped shape of the substrate holder 61. The channel133 of the liquid extractor 130 is provided in a part of the extractionbody 65 directly below a part of the substrate holder 61.

In the embodiment depicted in FIG. 25, the substrate holder 61 comprisesa network of fluid-carrying channels 161 configured to control thetemperature of the substrate holder 61. The substrate holder 61comprises an edge heater 203 at an outer edge of the substrate holder.The extraction body 65 comprises edge heaters 201, 202 at the outer andinner edges of the extraction body 65. The embodiment depicted in FIG.25 may be modified by replacing the edge heater 201, 202, 203 withfluid-carrying channels 161.

FIG. 26 depicts an embodiment of the present invention. In theembodiment depicted in FIG. 26, part of the liquid extractor 130 isprovided in the extraction body 65. The channel 133 is provided in theextraction body 65. Part of the passageway 132 is provided in theextraction body 65. The extraction body 65 has a stepped shape thatcorresponds to a stepped shape of the substrate holder 61, as in FIG.25. The substrate holder 61 comprises a network of fluid-carryingchannels 161 configured to control the temperature of the substrateholder 61. The extraction body 65 comprises edge heaters 201, 202positioned at outer and inner edges of the extraction body 65. Afluid-carrying channel 161 is provided in the substrate holder 61radially outward of the passageway 132 that connects the channel 133with the opening 131 of the liquid extractor 130. The embodimentdepicted in FIG. 26 may be modified by replacing the edge heater 201,202 with fluid-carrying channels 161.

In the embodiments depicted in FIGS. 24 to 26, the cover ring 112 may bethermally conditioned by one or more heater/temperature sensors, bysingle-phase conditioning, by two-phase conditioning, by one or morePeltier elements, by one or more fluid-carrying channels, or by anycombination of these components.

During use of the lithographic apparatus, the substrate table WT movesrelative to the liquid confinement structure IH such that the liquidconfinement structure IH is at a position directly over the substratetable WT. In an embodiment the substrate table WT is actuated to moverelative to the liquid confinement structure IH. The temperature of theliquid in the space 11 may be required to be controlled to within a fewthousandths of a Kelvin. This is because the temperature of the liquidin the space 11 affects the refractive index of the effective lens ofthe lithographic apparatus.

When the substrate table WT moves relative to the liquid confinementstructure IH such that the liquid confinement structure IH is at aposition over the substrate table WT, heat may be transferred betweenthe liquid in the space 11 and the substrate table WT. This heattransfer can undesirably cause the temperature of the liquid in thespace 11 to vary. It is desirable to provide a support apparatus 60 inwhich the heat transfer between the substrate table WT and the liquid inthe space 11 is reduced.

FIG. 27 depicts, in cross-section, part of a support apparatus 60according to an embodiment of the invention. The support apparatus 60comprises a table, such as a substrate table WT, and a body 271. Thebody 271 is positioned within a recess 279 of the substrate table WT.There is a gap 273 between the body 271 and the substrate table WT.

As depicted in FIG. 27, the support apparatus 60 comprises a member 274bridging the gap 273. The member 274 may be termed a seal member or aseal. The member 274 extends from a top surface 277 of the body 271 to atop surface 122 of the substrate table WT. Part of the member 274 is onthe top surface 277 of the body 271. Part of the member 274 ispositioned on the top surface 122 of the substrate table WT.

The substrate table WT is formed of a table material having a thermalconductivity. The member 274 comprises a thermal resistance layer 275.The thermal resistance layer 275 is formed of a thermal resistancematerial. The thermal resistance material has a lower thermalconductivity than the thermal conductivity of the table material.

The member 274 reduces the heat transfer between the substrate table WTand the liquid in the space 11 when the liquid confinement structure IHis directly over the substrate table WT. The thermal resistance layer275 serves as a resistance to heat transferring out of the substratetable WT towards the liquid in the space 11 and to heat transferring outof the liquid in the space 11 towards the substrate table WT. Due to thelow heat conductivity coefficient of the thermal resistance layer 275,the heat transfer from the table material towards the liquid in thespace 11 is reduced significantly compared to the situation in which thesubstrate table WT is in direct contact with the liquid in the space 11during use of the lithographic apparatus. Member 274 provides a thermalshield (e.g. a thermal isolator or thermal insulation) whichsubstantially reduces heat transfer between the liquid in the space 11and the substrate table WT.

The member 274 may be combined with any of the embodiments describedherein, particularly those described in relation to FIGS. 6 to 26. In anembodiment, the body 271 is an extraction body 65 as described above. Inan embodiment, the body 271 may be a substrate holder 61, or a sensor,for example. In the case that the body 271 is the extraction body 65,the top surface 277 of the body 271 corresponds to the top surface 105of the extraction body 65.

In an embodiment, the extraction body 65 and the substrate holder 61 arenot thermally decoupled from each other. In an embodiment, theextraction body 65 and the substrate holder 61 form a single component.The member 274 may extend from that single component to the top surface122 of the substrate table WT. In an embodiment, the gap 273 correspondsto the intermediate gap 75 as described above. In an embodiment, therecess 279 corresponds to the substrate holder recess 85 as describedabove.

As depicted in FIG. 27, in an embodiment, the body 271 is connected tothe substrate table WT via a plurality of burls 272. Instead of theburls 272, the body 271 may be connected to the substrate table WT byother means such as a vacuum clamp, a bolt, glue and/or a kinematic leafspring coupling.

FIG. 28 depicts, in cross-section, a support apparatus 60 according toan embodiment of the invention. In an embodiment, more of the member 274is on the top surface 122 of the substrate table WT than on the topsurface 277 of the body 271. In an embodiment, the member 274 extends,radially, further outwards along the top surface 122 of the substratetable WT than inwards along the top surface 277 of the body 271. Thismeans, referring to FIG. 27, that the distance D2 is greater thandistance D1.

The distance D2 indicates the extent to which the member 274 extends(e.g., radially) outwards along the top surface 122 of the substratetable WT. The distance D2 is measured in the outward (radial) directionfrom the inner edge of the recess 279 to the outer edge of the member274. The arrow at the bottom of FIG. 27 represents the (radially)outward direction. The distance D1 corresponds to the extent by whichthe member 274 extends (radially) inwards along the top surface 277 ofthe body 271. The distance D1 is calculated from the outer edge of thebody 271 to the inner edge of the member 274.

By providing that the member 274 is more on the top surface 122 of thesubstrate table D2 than on the top surface 277 of the body 271, themember 274 more efficiently reduces the thermal transfer between thesubstrate table WT and the liquid in the space 11 of the liquidconfinement structure IH.

As depicted in FIG. 28, in an embodiment the member 274 extends oversubstantially all of the top surface 122 of the substrate table WT. Inan embodiment, the member 274 is substantially continuous. The member274 may surround one or more components, such as one or more sensors,that are on the substrate table WT. The member 274 can prevent theliquid in the space 11 from coming into direct contact with thesubstrate table WT. The member 274 may reduce the thermal transferbetween all points of the top surface 122 of the substrate table WT withthe liquid in the space 11.

In an embodiment, the member 274 comprises a thermal adaptation layer276. The thermal adaptation layer 276 is formed of a thermal adaptationmaterial. Here the term thermal adaptation material is used to refer tothe material that forms the thermal adaptation layer 276. The thermaladaptation material adapts its temperature to the same temperature asthe liquid in the space 11. The thermal adaptation material has a lowerspecific heat capacity at 25° C. than a specific heat capacity at 25° C.of the table material. When the substrate table WT moves relative to theliquid confinement structure IH such that the liquid confinementstructure IH is at a position directly over the substrate table WT, theliquid in the space 11 may come into direct contact with the member 274.When the liquid in the space 11 comes into contact with the member 274comprising the thermal adaptation layer 276, the member 274 adapts itstemperature to the temperature of the liquid relatively quickly.

In an embodiment, the thermal adaptation layer 276 is positioned abovethe thermal resistance layer 275. In an embodiment, the thermaladaptation layer 276 forms a top surface of the member 274. The liquidin the space 11 comes into direct contact with the thermal adaptationlayer 276. Due to the low specific heat capacity of the thermaladaptation layer 276, the variation in temperature of the liquid in thespace 11 is very low. The low specific heat capacity of the thermaladaptation layer 276 means that a relatively small amount of energy istransferred between the liquid in the space 11 and the thermaladaptation layer 276 before the thermal adaptation layer 276 is at thesubstantially same temperature as the liquid in the space 11. Due to therelatively small amount of energy transfer, the variation in temperatureof the liquid in the space 11 is relatively low.

In an embodiment, the thermal adaptation material has a higher thermalconductivity than the thermal conductivity of the table material. Forheat transfer between the thermal adaptation layer 276 and the liquid inthe space 11, there may be a high transfer coefficient. When the liquidcomes into contact with the thermal adaptation layer 276, the member 274adapts its temperature to the temperature of the liquid quickly, partlydue to the high transfer coefficient.

In an embodiment, the thermal adaptation layer 276 has a thickness ofless than or equal to 50 micrometers, of less than or equal to 20micrometers, or of less than or equal to 10 micrometers. The thermaladaptation layer 276 is thin such that it has a low overall heatcapacity and does not significantly affect the coplanar relationshipbetween the top surface 122 of the substrate table WT and the substrateW, for example. When the liquid in the space 11 comes into contact withthe thermal adaptation layer 276, the variation in temperature of theliquid due to heat transfer between the member 274 and the liquid isrelatively low.

In an embodiment, the thermal adaptation material has a specific heatcapacity at 25° C. of less than or equal to 800 J/kgK or a specific heatcapacity at 25° C. of less than or equal to 600 J/kgK. By having a lowspecific heat capacity, the temperature variation in the liquid when theliquid comes into contact with the member 274 is relatively low.

In an embodiment, the thermal adaptation material is selected from agroup consisting of stainless steel and titanium. In an embodiment, amaterial that may be used for the thermal adaptation material comprisesaluminum, SiSIC, (Encapsulated) Thermal Pyrolytic Graphite and lithiumaluminosilicate glass-ceramic (such as Zerodur®). These materials may beless favorable than stainless steel and titanium because they have ahigher specific heat capacity. In an embodiment, the thermal adaptationmaterial is water-resistant. In an embodiment, the thermal adaptationmaterial has relatively high thermal resistance.

Stainless steel has a thermal conductivity of about 16 to 24 W/mK.Titanium has a thermal conductivity of about 15 to 23 W/mK. The thermalconductivity of the thermal adaptation material may be greater than thethermal conductivity of the table material. In an embodiment, thethermal conductivity of the thermal adaptation material is relativelylow. For example, stainless steel and titanium have relatively lowthermal conductivities compared to other metals that would bewater-resistant and have a low specific heat capacity.

In an embodiment, the thermal resistance layer 275 is between thethermal adaptation layer 276 and both the top surface 122 of thesubstrate table WT and the top surface 277 of the body 271. The liquidcomes into contact with the thermal adaptation layer 276 but not thethermal resistance layer 275.

In an embodiment, the thermal resistance material has a higher specificheat capacity at 25° C. than a heat capacity of the table material.

In an embodiment, the thermal resistance layer 275 has a thickness ofless than or equal to 50 micrometers, of less than or equal to 20micrometers, or of less than or equal to 10 micrometers. The thermalresistance layer 275 is thin so that the overall heat capacity of themember 274 is relatively low. When the member 274 comes into contactwith the liquid, the variation in temperature of the liquid isrelatively low due to the low heat capacity of the member 274.

In an embodiment, the thermal resistance material has a thermalconductivity of less than or equal to 0.5 W/mK, of less than or equal to0.1 W/mK, or of less than or equal to 0.05 W/mK. By having a relativelylow thermal conductivity and accordingly a high thermal resistance, themember 274, and in particular the thermal resistance layer 275, reducesthe thermal transfer between the table material of the substrate tableWT and the liquid in the space 11 when the liquid confinement structureIH is directly above the substrate table WT.

In an embodiment, the thermal resistance material is an adhesive. Thethermal resistance layer 275 may act to adhere the thermal adaptationlayer 276 to the substrate table WT and to the body 271. In anembodiment, the member 274 is a sticker.

In an embodiment, the thermal resistance material is selected from agroup consisting of an acrylate polymer, a silyl terminated polyether(such as MS Polymer®) and epoxy. In an embodiment, another material maybe used as the thermal resistance material. Epoxy may have a thermalconductivity within the range of from about 0.05 W/mK to about 0.35W/mK. Epoxy has a specific heat capacity at 25° C. of about 1000 J/kgK.

In an embodiment, the table material may be cordierite or Zerodur®.Zerodur® has a specific heat capacity at 25° C. of about 820 J/kgK.Zerodur® has a thermal conductivity of about 1.5 W/mK.

In an embodiment, the member 274 has a total thickness of less than orequal to 100 micrometers, of less than or equal to 50 micrometers, ofless than or equal to 20 micrometers, or of less than or equal to 10micrometers. The member 274 has a small total thickness such that itstotal heat capacity is relatively low. This reduces the temperaturevariation in the liquid that comes into contact with the member 274. Inan embodiment, the member 274 is thin such that it does notsignificantly adversely affect the flat top surface 122 of the substratetable WT.

In an embodiment, the member 274 has a mean thermal conductivity of lessthan or equal to 25 W/mK, of less than or equal to 15 W/mK or of lessthan or equal to 10 W/mK. Mean thermal conductivity refers to thethermal conductivity of the member 274 as a whole, rather than asub-portion of it. The member 274 has a low mean thermal conductivity soas to reduce heat transfer between the table material of the substratetable WT and the liquid in the space 11 when the liquid confinementstructure IH is directly above the substrate table WT.

In an embodiment, the member 274 has a mean specific heat capacity at25° C. of less than or equal to 1500 J/kgK, at 25° C. of less than orequal to 1000 J/kgK, or at 25° C. of less than or equal to 750 J/kgK.Mean specific heat capacity at 25° C. refers to the specific heatcapacity at 25° C. of the member 274 as a whole, rather than asub-portion of it. The member 274 has a low mean specific heat capacitysuch that the member 274 adapts its temperature relatively quickly tothe temperature of the liquid that comes into contact with the member274.

FIG. 29 depicts, in cross-section, a support apparatus 60 according toan embodiment of the invention. As depicted in FIG. 29, in anembodiment, the substrate table WT comprises a member recess 291. Themember 274 is at least partially within the member recess 291. Themember recess 291 reduces the extent by which the member 274 is above(if at all) the top surface 122 of the substrate table WT. In anembodiment, the member recess 291 has a depth that is substantiallyequal to the total thickness of the member 274. In an embodiment, themember 274 is substantially coplanar with the top surface 122 of thesubstrate table WT. In an embodiment, the top surface of the member 274is substantially coplanar with the substrate W in the case that thesubstrate is held by a substrate holder 61 in the substrate table WT.

FIG. 30 depicts, in cross-section, a part of a support apparatus of anembodiment. The extraction body 65 is substantially thermally decoupledand/or substantially mechanically decoupled from the substrate holder61.

In an embodiment, the extraction body 65 comprises a projection 30. Theprojection 30 is configured such that it surrounds the object holder(e.g. substrate holder 61). The projection 30 is configured such that,in use, a layer of liquid 32 is retained on the projection 30 and incontact with an object (e.g. substrate W) supported on the object holder(e.g. substrate holder 61).

In an embodiment, the projection 30 may be configured such that its topsurface 31 forms an annulus. The annulus extends around the inner regionof the extraction body 65. The annulus surrounds the substrate holder61. This may facilitate manufacture. In an embodiment the projection 30extends in the direction substantially normal to the substrate W. In anembodiment the top surface 31 of the projection 30 faces a lower surfaceof the substrate W.

In an embodiment, the projection 30 may be configured such that theseparation between the top surface 31 of the projection 30 and the lowersurface of a substrate W supported by the substrate holder 61 is about20 μm or less. In an embodiment, the projection may be configured suchthat the separation between the top surface 31 of the projection 30 andthe lower surface of a substrate W supported by the substrate holder 61is 10 μm or less.

In use, a layer of liquid 32 is retained on the projection 30, betweenthe top surface 31 of the projection 30 and the lower surface of thesubstrate W. The projection 30 is configured such that, in use, thelayer of liquid 32 prevents liquid from flowing from radially outward ofthe projection 30 to radially inward of the projection 30. This may beachieved because the capillary pressure of the layer of liquid 32retained on the projection 30 is greater than the force due to thepressure difference between radially outward of the projection 30 andradially inward of the projection 30. The capillary pressure is theforce necessary to force the layer of liquid 32 through the gap betweenthe substrate W and the projection 30 and is higher for smaller gaps.The capillary pressure is caused by the difference in pressure acrossthe interface between the layer of liquid 32 and the surrounding gas(e.g. air).

If the separation between the top surface 31 of the projection 30 andthe lower surface of the substrate W is too great (e.g. greater than 20μm, or greater than 10 μm), then the capillary pressure of the layer ofliquid 32 is not great enough to prevent liquid from flowing fromradially outward of the projection 30 to radially inward of theprojection 30. The smaller the separation, the greater the capillarypressure, and thereby the greater the function of preventing liquid fromflowing from radially outward of the projection 30 to radially inward ofthe projection 30.

The top surface 31 of the projection 30 does not come into contact withthe lower surface of the substrate W. Any such contact would beundesirable because it would adversely affect the flatness of thesubstrate W. For this reason, it may be desirable to provide a lowerlimit for the target separation between the top surface 31 of theprojection 30 and the lower surface of the substrate W. For example, inan embodiment the projection 30 is configured such that the separationbetween the top surface 31 of the projection 30 and the lower surface ofthe substrate W is 2 μm or more.

In an embodiment, the top surface 31 of the projection 30 is lower thanthe top surface 105 of the extraction body 65. This allows the substrateW to be positioned such that a peripheral region of the substrate W ispositioned directly above the projection 30. The top surface of thesubstrate W may be substantially coplanar with the top surface 105 ofthe extraction body 65.

In an embodiment, the substrate support apparatus 60 is configured suchthat, in use, part of the extraction body 65 extends under a peripheraledge of an object (e.g. a substrate W) supported on the object holder(e.g. a substrate holder 61). This is depicted in FIG. 30, which showsthat the inner peripheral region of the extraction body 65 overlaps withthe outer peripheral region of the substrate W in the radial direction.Liquid that flows from above the substrate W and/or above the extractionbody 65 may flow through the gap 5 between the extraction body 65 andthe substrate W. Liquid that flows through the gap 5 may be extractedvia the extraction opening 66, passageway 67 and channel 68 of theextraction body 65. By providing that the extraction body 65 reaches outto below the substrate W, such liquid is prevented from reaching thesubstrate holder 61.

In an embodiment, as shown in FIG. 30, the substrate holder 61 comprisessubstantially no liquid extractor of any kind. In an embodiment thesubstrate holder 61, in use, comes into contact with substantially noliquid used in the immersion lithographic apparatus. Liquid is extractedby only the extraction body 65, which is separated from the substrateholder 61. The substrate W is supported by only the substrate holder 61and not by the extraction body 65. In an embodiment, there is a completeseparation between the substrate supporting function (performed by thesubstrate holder 61) and the liquid capturing function (performed by theextraction body 65). In an embodiment, the substrate holder 61 is aseparate body from the extraction body 65. The thermal load caused bythe layer of liquid 32 on the projection 30 is minimal.

The substrate holder 61 performs a function of supporting the substrateW and performing accurate positioning. By arranging the substratesupport apparatus 60 such that the substrate holder 61 comes intocontact with substantially no liquid, the accuracy with which thesubstrate holder 61 positions the substrate W can be increased. This isbecause the substrate holder 61 is substantially unaffected by thermalloads caused by evaporation of liquid, for example.

By providing the projection 30, the possibility of liquid coming intocontact with the substrate holder 61 is avoided, thereby increasing theaccuracy of the substrate holder 61.

In an embodiment, the extent of overlap between the inner peripheralregion of the extraction body 65 and the outer peripheral region of thesubstrate W is about 0.5 mm or more. In an embodiment, the extent ofoverlap between the inner peripheral region of the extraction body 65and the outer peripheral region of the substrate W is about 3 mm orless.

In an embodiment, the extraction body 65 may comprise a channel 300. Thechannel 300 is connected to a passageway 301 that connects the channel300 to the passageway 80 of the extraction body 65. The channel 300 andthe passageway 301 are optional. The passageway 80 is positioned betweenthe lower surface of the substrate W and an upper surface of theextraction body 65. The passageway 80 is positioned immediately radiallyoutward of the projection 30. The passageway 80 extends below thesubstrate W.

In an embodiment, the channel 300 is in communication with a vacuum suchthat fluid is sucked from the passageway 80 through the passageway 301into the channel 300. In an embodiment, the channel 300 is incommunication with an overpressure and the passageway 301 connects thechannel 300 to the intermediate gap 75. In an embodiment the vacuum oroverpressure is controlled so as to force the layer of liquid 32radially outward and off the projection 30. This may be done beforeunloading the substrate W, for example. This makes it easier to removethe substrate W and makes it possible to export dry substrates.

In an embodiment the channel 300 is used to control the differencebetween the pressure radially outward of the projection 30 and thepressure radially inward of the projection 30 such that the pressuredifference is less than the capillary pressure of the layer of liquid32. This keeps the layer of liquid 32 on the projection 30.

In an embodiment, the passageway 301 does not connect the channel 300 tothe passageway 80 of the extraction body 65. Instead, in an embodimentthe passageway 301 connects the channel 300 to the intermediate gap 75between the extraction body 65 and the substrate holder 61. In this casethe channel is in communication with an overpressure. In an embodimentthe passageway 301 connects the passageway 80 to the channel 68, inwhich case the channel 300 may be omitted.

There is a possibility that the capillary pressure of the layer of fluid32 on the projection 30 causes the outer periphery of the substrate W tobe pulled downward. There is a risk that this reduces the flatness ofthe substrate W. The flatness may be reduced by an amount in the regionof about 10 nm. The effect of the capillary pressure on the flatness ofthe substrate W can be predicted and compensated for.

There is a possibility of bubbles congregating in the passageway 80close to the projection 30. This is because in the region immediatelyradially outward of the projection 30, the flow of fluid is at aparticularly low rate in both directions. In an embodiment, the channel300 and the passageway 301 may be used to suck any such bubbles or gaspockets from this corner of the passageway 80 of the extraction body 65.

In an embodiment, the extraction body 65 comprises thermal conditioningsystem such as a network of fluid-carrying channels 161 configured tocontrol the temperature of the extraction body 65. In an embodiment thefluid-carrying channels 161 carry thermal conditioning liquid. Thethermal conditioning liquid may be water, for example. Thefluid-carrying channels 161 maintain the temperature of the extractionbody 65 at a certain (e.g. predetermined) temperature. In an embodiment,one or more heater/temperature sensors (not shown) may be positioned inor near the fluid-carrying channels 161 so as to control the temperatureof the thermal conditioning liquid within the fluid-carrying channels161.

For a substrate support apparatus in which the substrate holder and theextraction body are formed as part of the same body (i.e. such thatthere is no intermediate gap 75), by providing such fluid-carryingchannels, the maximum substrate displacement due to a thermal loadcaused by extraction may be reduced by a factor of about two.Alternatively, by thermally decoupling the extraction body from thesubstrate holder (i.e. by providing the intermediate gap 75), themaximum substrate displacement due to a thermal load caused byextraction may be reduced by a factor of about six. Hence, thermaldecoupling of the extraction body from the substrate holder is aboutthree times more effective in reducing substrate displacement comparedto providing the fluid-carrying channels.

The combined effect of the thermal decoupling together with thefluid-carrying channels (or alternative temperature control mechanismssuch as edge heaters) is greater than the sum of the individual effects.In particular, it has been found that by providing the intermediate gap75 in combination with the fluid-carrying channels 161 (e.g. as depictedin FIG. 30), the maximum substrate displacement due to extraction isreduced by a factor of about 80 (which is significantly greater than2×6=12). The reason for this is explained below.

Although the thermal decoupling by providing the intermediate gap 75reduces the maximum substrate displacements by a factor of about six,the temperature difference across the substrate support apparatus 60 isincreased by a factor of about 10, which is undesirable. Providing thefluid-carrying channels 161 in the extraction body 65 is effective inreducing the temperature difference across the substrate supportapparatus 60. Accordingly, by providing the intermediate gap 75 and thefluid-carrying channels 161, the maximum substrate displacement isdecreased by such a great factor. In an embodiment, the intermediate gapis at least 0.2 mm. In an embodiment, the intermediate gap is at least0.5 mm. In an embodiment, the intermediate gap is at most 3 mm.

In an embodiment, the extraction body 65 comprises an edge heater 201 onan outer edge of the extraction body 65. In an embodiment, theextraction body 65 comprises an edge heater 204 on a lower surface ofthe extraction body 65. In an embodiment, the edge heaters 201, 204 areindependently controllable by the controller 500. The edge heaters 201,204 help maintain stability of the temperature profile of the substratesupport apparatus 60. Each of the edge heaters 201, 204 may comprise atemperature sensor. The edge heaters 201, 204 may be used in additionto, or as an alternative to, the fluid carrying channel 161.

The features depicted in the Figures may be combined with each other.Merely by way of example, the features of FIG. 30 may be combined withthe interface 81 of FIG. 8 and/or the cover ring 112 of FIG. 11.

In an embodiment there is provided a support apparatus comprising: atable formed of a table material having a thermal conductivity; a bodypositioned within a recess of the table, wherein there is a gap betweenthe body and the table; and a member bridging the gap from a top surfaceof the body to a top surface of the table, the member comprising athermal resistance layer of thermal resistance material having a lowerthermal conductivity than the thermal conductivity of the tablematerial.

In an embodiment, more of the member is on the top surface of the tablethan on the top surface of the body.

In an embodiment, the member extends further outwards along the topsurface of the table than inwards along the top surface of the body.

In an embodiment, the member extends over substantially the entire topsurface of the table.

In an embodiment, the member comprises a thermal adaptation layer ofthermal adaptation material having a lower specific heat capacity at 25°C. than a specific heat capacity at 25° C. of the table material.

In an embodiment, the thermal adaptation material has a higher thermalconductivity than the thermal conductivity of the table material.

In an embodiment, the thermal resistance layer is between the thermaladaptation layer and both the top surface of the table and the topsurface of the body.

In an embodiment, the thermal resistance material has a higher specificheat capacity at 25° C. than a specific heat capacity of the tablematerial.

In an embodiment, the thermal resistance material is an adhesive.

In an embodiment, the support apparatus further comprises an objectholder configured to support an object and wherein the body is anextraction body radially outward of the object holder, the extractionbody comprising an extraction opening configured to extract fluid from atop surface of the support apparatus, wherein the extraction body isspaced from the object holder such that the extraction body issubstantially decoupled from the object holder; wherein the extractionbody comprises a projection configured such that it surrounds the objectholder and such that, in use, a layer of fluid is retained on theprojection and in contact with an object supported on the object holder.

In an embodiment, the extraction body is disconnected from the objectholder such that the extraction body is detached from the object holder.

In an embodiment, the projection is configured such that, in use, thelayer of liquid prevents liquid from flowing from radially outward ofthe projection to radially inward of the projection.

In an embodiment, the extraction body is spaced from the object holderby an intermediate gap that comprises a vacuum or a gas.

In an embodiment, the object holder and at least part of the extractionbody are positioned within an object holder recess of the table, andwherein the extraction body is connected to the table at an interface.

In an embodiment, the interface is at a bottom surface and/or a radialsurface of the extraction body.

In an embodiment, the extraction body is connected to the table by avacuum clamp, a bolt, glue and/or a kinematic leaf spring coupling.

In an embodiment, the support apparatus further comprises an objectholder, wherein the body is an extraction body radially outward of theobject holder, the extraction body comprising an extraction openingconfigured to extract fluid from a top surface of the support apparatus,wherein the extraction body is connected to the object holder by aplurality of peripherally spaced joints such that, between the joints,the extraction body is spaced from the object holder.

In an embodiment, at least one of the joints extends from a top surfaceof the object holder only partially toward a bottom surface of theextraction body such that directly below the at least one joint theextraction body is spaced from the object holder.

In an embodiment, at least one of the joints comprises a jointconditioning system configured to supply heat energy to and/or removeheat energy from the joint and/or between the joints.

In an embodiment, the joints, in total, extend along at most 10% of aperiphery between the object holder and the extraction body.

In an embodiment, the object holder and at least part of the extractionbody are positioned within an object holder recess of the table.

In an embodiment, the extraction body comprises a projection configuredsuch that it surrounds the object holder and such that, in use, a layerof liquid is retained on the projection and in contact with an objectsupported on the object holder.

In an embodiment, the projection is configured such that, in use, thelayer of liquid prevents liquid from flowing from radially outward ofthe projection to radially inward of the projection.

In an embodiment, a top surface of the projection is lower than a topsurface of the extraction body.

In an embodiment, the support apparatus is configured such that, in use,part of the extraction body extends under a peripheral edge of an objectsupported on the object holder.

In an embodiment, the extraction body comprises a main body and a coverring positioned at a top surface of the main body, wherein the member ison top of the cover ring.

In an embodiment, the cover ring extends radially outward beyond aradial extent of the main body.

In an embodiment, the cover ring extends substantially to a fiduciarymarker at the top surface of the table of the support apparatus.

In an embodiment, the extraction body comprises an extraction bodyconditioning system configured to supply heat energy to and/or removeheat energy from the extraction body.

In an embodiment, the extraction body conditioning system comprises aplurality of conditioning units that are independently controllable,wherein each of the plurality of conditioning units is configured tosupply heat energy to and/or remove heat energy from a respectiveconditioning region of the extraction body.

In an embodiment, the extraction body conditioning system comprises anetwork of fluid-carrying channels configured to control the temperatureof the extraction body.

In an embodiment, the extraction body conditioning system comprises acooling channel containing carbon dioxide at a pressure such that thecarbon dioxide has a boiling point of at most 30° C. or at most 22° C.

In an embodiment, the extraction body conditioning system comprises aheat pipe.

In an embodiment, the support apparatus of any of claims comprises aliquid extractor radially inward of the extraction opening andconfigured to extract liquid from a top surface of the object holder.

In an embodiment, the extraction body comprises at least part of theliquid extractor.

In an embodiment, the liquid extractor comprises a liquid extractorconditioning system configured to supply heat energy to and/or removeheat energy from the liquid extractor.

In an embodiment, the extraction body comprises an extraction bodyconditioning system configured to supply heat energy to and/or removeheat energy from the extraction body, and wherein the liquid extractorconditioning system and the extraction body conditioning system areindependently controllable.

In an embodiment, the liquid extractor conditioning system comprises anetwork of fluid-carrying channels configured to control the temperatureof the liquid extractor.

In an embodiment, a space between the extraction body and the objectholder is continuous peripherally and continuous from an upper surfaceof the extraction body to a bottom surface of the extraction body.

In an embodiment, the object holder is a substrate holder.

In an embodiment, there is provided a device manufacturing method usinga lithographic apparatus, the method comprising: projecting a beampatterned by a patterning device onto a substrate while supporting thesubstrate with a support apparatus, wherein the support apparatuscomprises: a table formed of a table material having a thermalconductivity; a body positioned within a recess of the table, whereinthere is a gap between the body and the table; and a member bridging thegap from a top surface of the body to a top surface of the table, themember comprising a thermal resistance layer of thermal resistancematerial having a lower thermal conductivity than the thermalconductivity of the table material.

In an embodiment, there is provided a support apparatus for alithographic apparatus, comprising: an object holder configured tosupport an object; and an extraction body radially outward of the objectholder, the extraction body comprising an extraction opening configuredto extract fluid from a top surface of the support apparatus, whereinthe extraction body is spaced from the object holder such that theextraction body is substantially decoupled from the object holder,wherein the extraction body comprises a projection configured such thatit surrounds the object holder and such that, in use, a layer of liquidis retained on the projection and in contact with an object supported onthe object holder.

In an embodiment, the support apparatus is configured such that, in use,a capillary pressure of the layer of liquid is greater than a pressuredifference between radially outward of the projection and radiallyinward of the projection, thereby preventing the fluid from flowing fromradially outward of the projection to radially inward of the projection.In an embodiment, the extraction body is spaced from the object holderby an intermediate gap that comprises a vacuum or a gas. In anembodiment, the support apparatus is configured such that, in use, partof the extraction body extends under a peripheral edge of an objectsupported on the object holder.

In an embodiment, there is provided a support apparatus for alithographic apparatus, comprising: an object holder; and an extractionbody radially outward of the object holder, the extraction bodycomprising an extraction opening configured to extract fluid from a topsurface of the support apparatus, wherein the extraction body isconnected to the object holder by a plurality of peripherally spacedjoints such that, between the joints, the extraction body is spaced fromthe object holder.

In an embodiment, at least one of the joints extends from a top surfaceof the object holder only partially toward a bottom surface of theextraction body such that directly below the at least one joint theextraction body is spaced from the object holder. In an embodiment, atleast one of the joints comprises a joint conditioning system configuredto supply heat energy to and/or remove heat energy from the joint and/orbetween the joints. In an embodiment, the joints, in total, extend alongat most 10% of a periphery between the object holder and the extractionbody, wherein the joints are substantially evenly distributed along thewhole circumference of the periphery. In an embodiment, the extractionbody comprises a main body and a cover ring positioned at a top surfaceof the main body. In an embodiment, the cover ring extends radiallyoutward beyond a radial extent of the main body. In an embodiment, theextraction body comprises an extraction body conditioning systemconfigured to supply heat energy to and/or remove heat energy from theextraction body. In an embodiment, the extraction body conditioningsystem comprises a plurality of conditioning units that areindependently controllable, wherein each of the plurality ofconditioning units is configured to supply heat energy to and/or removeheat energy from a respective conditioning region of the extractionbody. In an embodiment, the extraction body conditioning systemcomprises a network of fluid-carrying channels configured to control thetemperature of the extraction body. In an embodiment, the extractionbody conditioning system comprises a cooling channel containing carbondioxide at a pressure such that the carbon dioxide has a boiling pointof at most 30° C. or at most 22° C. In an embodiment, the supportapparatus comprises a liquid extractor radially inward of the extractionopening and configured to extract liquid from a top surface of theobject holder. In an embodiment, the extraction body comprises at leastpart of the liquid extractor. In an embodiment, the liquid extractorcomprises a liquid extractor conditioning system configured to supplyheat energy to and/or remove heat energy from the liquid extractor. Inan embodiment, the extraction body comprises an extraction bodyconditioning system configured to supply heat energy to and/or removeheat energy from the extraction body, and wherein the liquid extractorconditioning system and the extraction body conditioning system areindependently controllable. In an embodiment, the liquid extractorconditioning system comprises a network of fluid-carrying channelsconfigured to control the temperature of the liquid extractor. In anembodiment, the object holder is a substrate holder. In an embodiment,the support apparatus comprises a table formed of a table materialhaving a thermal conductivity, the extraction body positioned within arecess of the table and there is a gap between the extraction body andthe table; and a member bridging the gap from a top surface of theextraction body to a top surface of the table, the member comprising athermal resistance layer of thermal resistance material having a lowerthermal conductivity than the thermal conductivity of the tablematerial. In an embodiment, more of the member is on the top surface ofthe table than on the top surface of the extraction body. In anembodiment, the member extends further outwards along the top surface ofthe table than inwards along the top surface of the extraction body. Inan embodiment, the member extends over substantially the entire topsurface of the table. In an embodiment, the member comprises a thermaladaptation layer of thermal adaptation material, the thermal adaptationmaterial having a lower specific heat capacity at 25° C. than a specificheat capacity at 25° C. of the table material. In an embodiment, thethermal adaptation material has a higher thermal conductivity than thethermal conductivity of the table material. In an embodiment, thethermal resistance layer is between the thermal adaptation layer andboth the top surface of the table and the top surface of the extractionbody. In an embodiment, the thermal resistance material has a higherspecific heat capacity at 25° C. than a specific heat capacity of thetable material.

In an embodiment, there is provided a lithographic apparatus comprisinga support apparatus as described herein.

In an embodiment, there is provided a device manufacturing method usinga lithographic apparatus, the method comprising: projecting a beampatterned by a patterning device onto a substrate while supporting thesubstrate with a support apparatus, wherein the support apparatuscomprises: an object holder configured to support an object; and anextraction body radially outward of the object holder, the extractionbody comprising an extraction opening configured to extract fluid from atop surface of the support apparatus, wherein the extraction body isspaced from the object holder such that the extraction body issubstantially decoupled from the object holder, wherein the extractionbody comprises a projection configured such that it forms an annulusthat surrounds the object holder and such that, in use, a layer of fluidis retained on the projection and in contact with an object supported onthe object holder.

In an embodiment, there is provided a device manufacturing method usinga lithographic apparatus, the method comprising: projecting a beampatterned by a patterning device onto a substrate while supporting thesubstrate with a support apparatus, wherein the support apparatuscomprises: an object holder; and an extraction body radially outward ofthe object holder, the extraction body comprising an extraction openingconfigured to extract fluid from a top surface of the support apparatus,wherein the extraction body is connected to the object holder by aplurality of peripherally spaced joints such that, between the joints,the extraction body is spaced from the object holder.

Although specific reference may be made in this text to the use oflithographic apparatus in the manufacture of ICs, it should beunderstood that the lithographic apparatus described herein may haveother applications, such as the manufacture of integrated opticalsystems, guidance and detection patterns for magnetic domain memories,flat-panel displays, liquid-crystal displays (LCDs), thin film magneticheads, etc. The skilled artisan will appreciate that, in the context ofsuch alternative applications, any use of the terms “wafer” or “die”herein may be considered as synonymous with the more general terms“substrate” or “target portion”, respectively. The substrate referred toherein may be processed, before or after exposure, in for example atrack (a tool that typically applies a layer of resist to a substrateand develops the exposed resist), a metrology tool and/or an inspectiontool. Where applicable, the disclosure herein may be applied to such andother substrate processing tools. Further, the substrate may beprocessed more than once, for example in order to create a multi-layerIC, so that the term substrate used herein may also refer to a substratethat already contains one or multiple processed layers.

The terms “radiation” and “beam” used herein encompass all types ofelectromagnetic radiation, including ultraviolet (UV) radiation (e.g.having a wavelength of or about 436, 405, 365, 248, 193, 157 or 126 nm).The term “lens”, where the context allows, may refer to any one orcombination of various types of optical components, including refractiveand reflective optical components.

While specific embodiments of the invention have been described above,it will be appreciated that the invention may be practiced otherwisethan as described. For example, the embodiments of the invention maytake the form of a computer program containing one or more sequences ofmachine-readable instructions describing a method as disclosed above, ora data storage medium (e.g. semiconductor memory, magnetic or opticaldisk) having such a computer program stored therein. Further, themachine readable instruction may be embodied in two or more computerprograms. The two or more computer programs may be stored on one or moredifferent memories and/or data storage media.

Any controllers described herein may each or in combination be operablewhen the one or more computer programs are read by one or more computerprocessors located within at least one component of the lithographicapparatus. The controllers may each or in combination have any suitableconfiguration for receiving, processing, and sending signals. One ormore processors are configured to communicate with the at least one ofthe controllers. For example, each controller may include one or moreprocessors for executing the computer programs that includemachine-readable instructions for the methods described above. Thecontrollers may include data storage media for storing such computerprograms, and/or hardware to receive such media. So the controller(s)may operate according the machine readable instructions of one or morecomputer programs.

One or more embodiments of the invention may be applied to any immersionlithography apparatus, in particular, but not exclusively, those typesmentioned above and whether the immersion liquid is provided in the formof a bath, only on a localized surface area of the substrate, or isunconfined. In an unconfined arrangement, the immersion liquid may flowover the surface of the substrate and/or substrate table so thatsubstantially the entire uncovered surface of the substrate table and/orsubstrate is wetted. In such an unconfined immersion system, the liquidsupply system may not confine the immersion liquid or it may provide aproportion of immersion liquid confinement, but not substantiallycomplete confinement of the immersion liquid.

A liquid supply system as contemplated herein should be broadlyconstrued. In certain embodiments, it may be a mechanism or combinationof structures that provides a liquid to a space between the projectionsystem and the substrate and/or substrate table. It may comprise acombination of one or more structures, one or more fluid openingsincluding one or more liquid openings, one or more gas openings or oneor more openings for two phase flow. The openings may each be an inletinto the immersion space (or an outlet from a fluid handling structure)or an outlet out of the immersion space (or an inlet into the fluidhandling structure). In an embodiment, a surface of the space may be aportion of the substrate and/or substrate table, or a surface of thespace may completely cover a surface of the substrate and/or substratetable, or the space may envelop the substrate and/or substrate table.The liquid supply system may optionally further include one or moreelements to control the position, quantity, quality, shape, flow rate orany other features of the liquid.

The descriptions above are intended to be illustrative, not limiting.Thus, it will be apparent to one skilled in the art that modificationsmay be made to the invention as described without departing from thescope of the claims set out below.

The invention claimed is:
 1. A support apparatus for a lithographicapparatus, the support apparatus comprising: a support sectionconfigured to support an object; and an extraction body horizontallyoutward of the support section, the extraction body comprising anexhaust opening configured to exhaust fluid from a surface of thesupport apparatus, wherein the extraction body is spaced from thesupport section by an open gap, wherein the open gap is spanned by astructure such that the open gap extends below the structure and an openspace above the structure contacts the structure, and wherein theexhaust opening is located above the structure.
 2. The support apparatusof claim 1, wherein the open gap extends around the support section. 3.The support apparatus of claim 1, wherein an uppermost surface of theextraction body adjacent the support section is generally coplanar withan upper surface of the object when supported by the support section. 4.The support apparatus of claim 1, wherein the structure is a separatebody from the support section and the extraction body.
 5. The supportapparatus of claim 1, wherein the extraction body comprises a heatexchange device arranged to directly thermally condition the extractionbody.
 6. The support apparatus of claim 1, wherein the extraction bodyis essentially mechanically isolated from at least the support section.7. The support apparatus of claim 1, wherein the extraction body isessentially thermally isolated from at least the support section.
 8. Asupport apparatus for a lithographic apparatus, the support apparatuscomprising: a support section configured to support an object; and anextraction body horizontally outward of the support section, theextraction body comprising: an exhaust opening configured to exhaustfluid from a surface of the support apparatus, the exhaust openingconnected to a channel, at least part of the channel extending with ahorizontal direction component, and a cover structure configured to atleast partly surround the object, the cover structure covering over theat least part of the channel, wherein at least the cover structure isremovably held in the support apparatus.
 9. The support apparatus ofclaim 8, wherein an uppermost surface of the extraction body adjacentthe support section is generally coplanar with an upper surface of theobject when supported by the support section.
 10. The support apparatusof claim 8, further comprising a solid member spanning an open gapbetween the extraction body and the support section.
 11. The supportapparatus of claim 10, wherein the open gap extends around the supportsection and wherein the exhaust opening is located above the solidmember.
 12. The support apparatus of claim 8, wherein the extractionbody is essentially mechanically isolated from at least the supportsection.
 13. The support apparatus of claim 8, wherein the extractionbody is essentially thermally isolated from at least the supportsection.
 14. The support apparatus of claim 8, wherein the extractionbody comprises a heat exchange device arranged to directly thermallycondition the extraction body.
 15. A support apparatus for alithographic apparatus, the support apparatus comprising: an objecttable having a support section configured to support an object, an edgeof the support apparatus surrounds the support section; and anextraction body located horizontally outward of the support section andhaving a surface spaced by a gap from, and facing toward, a surface atthe edge of the support apparatus, the extraction body comprising anexhaust opening configured to exhaust fluid from a surface of thesupport apparatus, the exhaust opening connected to a channel, at leastpart of the channel located horizontally outward of the support sectionand extending with a horizontal direction component.
 16. The supportapparatus of claim 15, wherein a structure spans a gap between theextraction body and the edge of the support apparatus, wherein the edgeof the support apparatus is located outward of the extraction body. 17.The support apparatus of claim 15, wherein a structure spans a gapbetween the extraction body and the support section.
 18. The supportapparatus of claim 15, wherein the extraction body is essentiallymechanically isolated from at least the support section.
 19. The supportapparatus of claim 15, wherein the extraction body is essentiallythermally isolated from at least the support section.
 20. The supportapparatus of claim 15, wherein the extraction body is spaced by an opengap from the support section and by an open gap from the edge of thesupport apparatus, wherein the edge of the support apparatus is locatedoutward of the extraction body.